Minimize button ("-") doesn’t work for Scene, Game, Hierarchy etc. windows on Mac.

Steps to reproduce:
1. Create a new project.
2. Undock Scene view.
3. Click the minimize button ("-") on the upper right corner of Scene view.

Actual result:
Minimize button doesn't work.

Expected result:
Window minimizes when button clicked.

Note:
1. Minimize button was removed in 2019.1.0a10 and 2019.1.0a11.
2. Minimize button not available on the Windows platform.
3. The same issue observed for all other windows like the Game view, inspector, Hierarchy, Project, Console, Lighting setting, Animation, Animator, Delete Layout etc.

Reproducible On: 2019.2.0a1, 2019.1.0a14, 2019.1.0a12

Working fine On: 2019.1.0a11, 2018.3.0f2

Environment:
Occurring on Mac only.